cygwin rsync performance and bandwidth between two w2003 servers

Ulrich Jung ulrich.jung at
Thu Sep 14 11:42:49 GMT 2006

Hi Quinn,

it's a local filesystem (SCSI U320)...
I tried it also with the --bwlimit switch but that doesn't matter - it's 
still the same.
This morning I took a closer look at the transfer rate between w2003 and 
linux: unfortunally it's not the whole bandwidth but only 75% of it. And 
that's not protocol overhead or something like that because I checked it 
with iptraf on our proxy server. Only between two linux systems I'm able 
to get maximum speed.

Perhaps some more ideas?

Sattler Media Press GmbH
Ulrich Jung
Kurt-Sattler-Straße 9 - 38315 Hornburg
Fon +49 5334 29 152
Fax +49 5334 29 344
mailto:ulrich.jung at

Quinn Snyder schrieb:
> Ulrich,
> Just out of curiousity...
> What is the filesystem that you are trying to back up?
> Are you running a networked shared system or is it local through a SCSI or
> SATA interface?  If its networked, you may want to try the --whole-file
> switch.
> If you are indeed running a local system, just for kicks and grins, maybe
> try the --bwlimit switch.  I know that you are running a 2mb link between
> the two.  But you may want to try and tell your system what your theoretical
> max bandwidth is.  For some reason it may only think it’s a 1mb link. (don't
> know why, unless something is messy in the windows-linux transition).
> Hope this helps.
> Quinn Snyder
> Network Technician/Linux Administrator
> IP Phone: +1(602)748-4281
> q.snyder at
> -----Original Message-----
> From: Ulrich Jung [mailto:ulrich.jung at] 
> Sent: Tuesday, September 12, 2006 4:49 AM
> To: rsync at
> Subject: cygwin rsync performance and bandwidth between two w2003 servers
> I have two Windows 2003 Standard Edition Server with 2x 3,0 GHz P4 and 4 
> On each server rsync runs as cygwin daemon (rsync version 2.6.6; 
> protocol version 29).
> The two servers are connected through a 2 MBit VPN link.
> When I sync a single large file or a whole directory, rsync only uses 
> 50% of the available bandwidth.
> When I do the same between windows and linux server, rsync takes the 
> whole bandwidth.
> Both windows and linux server have the same settings in rsyncd.conf.
> Would be great if there is someone with any ideas how to solve this problem!
> Thanks,

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